Operating mechanism for vibrating tables



p 1952 R. EMMONS 2,610,040

OPERATING MECHANISM FOR VIBRATING TABLES Filed July 21, 1951 2 SHEETS SHEET l IN V EN T OR. Fig flnmo/zs BY Sept. 9, 1952 R. EMMONS 2,610,040

I OPERATING MECHANISM FOR VIBRATING TABLES Filed July 21 1951 2 SHEETS-SHEET 2 INVENTOR.

fi y 5222220125 BY Patented Sept. 9, 1952 'OPERATING MECHANISM FOR VIBRATING TABLES Roy Emmons, F011, Laufl d a. Application July 21, 195 Serial No. 237,954

3 Claims.

This invention-relates to a vibrating table of the kindwhereon may be rested portable molds, single-or'multiple cavity, for plastic concrete and thelike thel purpose being to rapidly shake each moldthrou'gha brief period whereby to facilitate the escape of airand excess water'from the concrete mi'xthereby'to densify the solid particles in the-mixahda'greatly expedite the setting of the oasting. Such 'a vibrating table must be sturdyand capableof withstanding rough usage, usually'out in theopen where the production of concrete castings is to be carried on.

Theipresent vibrating table is advantageous because of its simplicity and 'sturdiness, and the dependability with which it operates. Itconsists of but few parts, and the operation thereof is controlle'd by a sin'glelever which may be swung by pressure from' a standing' workmans thigh, thereby "leaving his hands free to remove any excess concrete mm the mold or molds undergoing treatment, keeping the table top clean, etc. The mechanism incorporated into the present table involves a continuously running motor with a clutch-incorporated in the drive whereby to transmit vibratory movements to the table top for'thede'sired period of'time. It also involves a brake operable whenthe clutch is disengaged so as to bring the vibrating mechanism to a quick stop. The singlecontrol operates to release the brake concurrently with engagement of the K clutch, and to set the brakeeoncurrently with disengagement of the clutch.

A suggestive embodiment of this invention in a practical-form is illustrated in the accompanying drawing wherein- Figure lis anendelevation of the stand whereon -are mounted -the operating parts including the vibrating table top; t

Fig. --2 is a top plan view of the stand with a portion ofthe table broken away to exhibit cer tain parts therebelow;

Fig. 3 is .a detail in vertical section, taken on line's- 3 ofFigIZL r Fig. '4 is-a detail in vertical section, taken on line i- 4 of Fig/3;

'5 is a front tabletop;

.6 isan enlarged 'detail in section of the jack 'shaft,the bearings therefor, and the various pulleys and collars mounted thereon; and

Fig.7 is a detail in section, taken on line i--? of Fig. 5.

The vibrating table comprises a stand having fouran'gle iron legs Ill surmounted by a rectangular frame of angle irons H, the legs being inelevation of the stand and r the inner brace l3 and the 2 terbraced by angleiron rails 12. Between two opposite rails 12 is'supportedan innerbr'ace 13. The frame legs andbraces, at their points of connection, are suitably joined'as by Welding. A heavy table top I5 of approximately thesame olimensions as the "stand frame is'yieldingly supported thereabove in spaced relation thereto by a plurality of coiled springs 10, arrangedone at each corner with one sprin therebetween, making a total of eight springs altogether (see Fig. 2). Each spring at its opposite ends is joined to the stand and tabletop in any suitable manner. p

To the underside of the table top I5 is affixed a pair of aligned bearings lflspaced widely apart and arranged close toits center line (see Fig. 2). A shaft 26 which is jourh'al'edfor rotation in the bearings supports therebe'yondat each of its opposite ends an off balajncd collar 2! which is fixedly secured thereto asby a set screw 22. Each collar is unbalanced with respect to the shaft axis, as by forming a 'pairof angular flat faces a and b which are radially much closer to the shaft axis than the concentric portion 0 of the collar periphery. The rotative adjustments of the two collars are alike. When the shaft20 is rotated, the two off-balanced collars will produce vibrations of considerable amplitude whereby totra'ns mit to the table top I5 a like shaking and vibrating movement.

At a point intermediately of "the bearings 18 a grooved pulley24- is affixed to. the shaft, and thereover is fitted an endless belt 25 which runs over a grooved pulley 26 that is carried faston a jack shaft 21 which is rotatably supported close to the front of the sta nd nea r its opposite ends, by bearings 28and 29 which are carried on two of the adjacent rails l2 and I3 (seeFig. 6). A second groovedpulley 3| mounted loosely on the jack shaft andspace'd slightly from the pulley 26 receives thereover an endless belt 32 which is trained over agrooved drive pulley 33 mounted fast on the shaft 34 ofa motor 35 which is supported on a base plate 36 extending between proximate bracev rail it. By reference toFig. 1 it wm'be observedthat the motor 34 is located toward the rear of the stand, the jack shaft 21 is located tow'ardits front, and that both are disposed at a low-down point on the stand so that the axes of the motor and jack shaft are ina plane that is generally horizontal. It will be noted'fur'tlier that vertical vibrations which are pr'oducedin the table I5 through rotation of the off-balanced shaft "2 0 are dissipated in and absorbed by the generally verti- 3 cal belt which is connected with the jack shaft 2! sufiiciently loosely to achieve this end.

The jack shaft is so mounted as to have capacity for a slight axial movement. A pair of clutch faces 38 and 39 is carried upon the confronting ends of the pulleys 26 and 3|, respectively. When the shaft 21 is shifted rightward, these clutch faces will interengage so as to establish a driving connection between the pulley 3| and the shaft 21, but when in its normal leftward position the drive will be disestablished so that the jack shaft will remain motionless. A thrust bearing 4| is mounted on the shaft 21 adjacent its supporting bearing 28 but normally spaced slightly from the hub of the pulley 26 when the jack shaft is not operating. When the pulley 3| is shifted rightwise, however, in response to axial pressure exerted thereon by a yoke collar 42 that is loose on the shaft, a driving engagement is produced between the clutch faces 33 and 39, thereby to rotate the jackshaft. Further rightward movement of the yoke collar 42 will cause the jack shaft itself to be shifted to the point of the hub of the pulley 26 engaging the thrust bearing 4|. Beyond the shaft bearing 28 a collar 43 is afiixed to the shaft near its end, largely as a precautionary measure.

The bearing 29 near the opposite end of the jack shaft 21 is flanked on its inner end by a brake disc 45 which is aflixed thereto in coacting relation to a brake disc 46 that is mounted fast on the shaft; and on its outer end by an inner thrust bearing 41 spaced from an outer thrust bearing 48 by an intervening compression spring 50. A stop collar 5| afiixed to the shaft at the outer end of the outer thrust bearing completes the brake assembly. The spring 50, always under compression, urges the jack shaft leftwise and in so doing separates the pulleys 26 and 3| so as to disestablish any driving connection therebetween; this leftwise shift of the shaft also advances the brake disc 46 fast thereon into en agement with the brake disc 45 that is fast on the bearing 29, thereby acting to brake the shaft and hold it against rotation.

A control whereby the shaft may be manually shifted rightwise counter to the tension of the spring 50 is also provided. As herein shown, this comprises a vertical rod 53 at the front side of the stand and laterally extended at its top end to provide an operating lever 54. Near its lower end the rod is rotatably supported in a bearing 55 that is carried by the front brace rail l2; a bearing plate 56 affixed to the front frame iron furnishes a support for the control rod near its upper end (see Fig. 1)

Aflixed to the rod oppositely of the jack shaft 21 is a pair of laterally extending arms 51 constituting a yoke which pivotally mounts a pair of aligned pins 58 in connection with the collar 42 at diametrically opposite points. Whenever the control rod 53 is swung through its short range of movement to shift the collar 42 to the right, it will force the two clutch faces 38 and 39 to interengage, thereby to produce rotation of the jack shaft; while this condition continues the two brake discs 45 and 46 are maintained in separated relation so that the jack shaft is free to operate, the spring 50 meanwhile being placed under an enhanced compression. Upon releasing the control rod, the spring will act to shift the jack shaft leftward to its normal position of rest, and in so doing the clutch connection is broken while the two brake discs become interengaged. The establishment or disestablishment of the driving connection is accompanied always by a concurrent release or setting of the shaft brake, thereby freeing the shaft for initiation of its operation and subsequently, and checking the shaft rotation quickly at the conclusion of its operation.

In operation, a workman will find it convenient to stand at the front side of the stand with one thigh close to the lever 54 of the control rod. Under the influence of the spring 50 the jack shaft will normally remain in a leftward position where (l) the brake is set and (2) the clutch is disengaged. When the table top I5 has been loaded the Workman moves slightly to the left to swing the lever correspondingly, thereby advancing the clutch collar 42 rightwise to produce a corresponding shift of the jack shaft and concurrently (1) release of the brake and (2) engagement of the clutch with consequent operation of the jack shaft. This operation will continue so long as the control lever is held in this leftward position; but when released, as by the workman moving slightly to the right, the spring 50 will shift the jack shaft leftward whereupon the clutch is disengaged and the brake is set to produce a quick stop of the jack shaft. The table top is now still so that the load which has been vibrated is ready for removal and replacement by a newload that is to undergo vibration.

In practice, where molds containing concrete in a plastic state are to be given the vibratory treatment, the off-balanced shaft carried by the table to may be operated at a. speed of 3,000 R. P. M. or more for relatively brief periods. The effect on freshly poured concrete in the molds so vibrated is to expel the air and force the water to the surface, thereby densifying the casting and reducing thetime for setting to a half or more. As an example, a single vibrating table, 32 X 32", when used to treat multiple cavity molds for slump bricks,'will step up the production to as high as 30,000 bricks per day.

I claim:

1. Operating mechanism for an off-balanced vibrating shaft rotatably carried on the under face of amold supporting table top having a vertically movable resilient mounting on the top of a stand, comprising a jack shaft mounted for rotation on the stand at a relatively low point near the front side thereof, a continuously operated motor having a shaft rotatable about an axis parallel with the jack shaft and mounted on the stand toward the rear side thereof at a relatively low point, a pulley on the motor shaft,

. a pulley on the off-balanced shaft, two pulleys on the jack shaft, one of said last mentioned pulleys being fixed on the jack shaft to rotate therewith, the other pulley on the jack shaft being mounted for free rotation thereon and for movement axially toward and from the other pulley, coacting clutch faces on the two pulleys on the jack shaft whereby to transmit motion therebetween when the clutch faces are interengaged, an endless belt connecting the motor shaft pulley and the loose pulley on the jack shaft, a second endless belt connecting the fixed pulley on the jack shaft and the off-balanced shaft pulley to produce cooperation thereof with consequent vibrations of the table top vertically of the stand, the endless belt driving the offbalanced shaft being disposed in a generally vertical direction and with sufficient slack endwise thereof to leave the table top free for vibrations vertically of the stand, and control means providing for axially moving the loose pulley on the jack shaft toward and from the fixed pulley thereon, whereby to engage and disengage the clutch faces to cause operation and non-operation of the jack shaft and the off-balanced table top shaft.

2. Operating mechanism for an off-balanced vibrating shaft rotatably carried on the under face of a mold supporting table top having a vertically movable resilient mounting on the top of a stand, comprising a jack shaft mounted for rotation on the stand at a relatively low point near the front side thereof, the mounting for the jack shaft permitting limited axial movement thereof, a continuously operated motor having a shaft rotatable about an axis parallel with the jack shaft and mounted on the stand toward the rear side thereof at a relatively low point, a pulley on the motor shaft, a pulley on the off-balanced shaft, two pulleys on the jack shaft, one of said last mentioned pulleys being fixed on the jack shaft to rotate therewith, the other pulley on the jack shaft being mounted for free rotation thereon and for movement axially toward and from the other pulley, coacting clutch faces on the two pulleys on the jack shaft whereby to transmit motion therebetween when the clutch faces are interengaged, an endless belt connecting the motor shaft pulley and the loose pulley on the jack shaft, a second endless belt connecting the fixed pulley on the jack shaft and the off-balanced shaft pulley to produce cooperation thereof with consequent vibrations of the table top vertically of the stand, the endless belt driving the off-balanced shaft being disposed in a generally vertical direction and with sufficient slack endwise thereof to leave the table top free for vibrations vertically of the stand, control means providing for axially moving the loose pulley on the jack shaft toward and from the fixed pulley thereon, whereby to engage and disengage the clutch faces to cause operation and non-operation of the jack shaft and the off-balanced table top shaft, a compression spring urging the jack shaft axially in one direction, and a brake comprising two coacting parts, one fast on the jack shaft and the other fixed with respect to said stand, and one of said parts normally interengaging with the other when the jack shaft is shifted axially in response to tension of the spring whereby to hold the jack shaft against rotation, the control means, when operated to axially move said loose pulley on the jack shaft to cause engagement of the clutch faces of said pulleys, shifting the jack shaft counter to tension of said spring and thereby releasing the brake and freeing the jack shaft for operation.

3. Operating mechanism for an off-balanced vibrating shaft rotatably carried on the under face of a mold supporting table top having a vertically movable resilient mounting on the top of a stand, comprising a jack shaft mounted for rotation on the stand at a relatively low point near the front side thereof, the mounting for the jack shaft permitting limited axial movement thereof, a continuously operated motor having a shaft rotatable about an axis parallel with the jack shaft and mounted on the stand toward the rear side thereof at a relatively low point, a pulley on the motor shaft, a pulley on the offbalanced shaft, two pulleys on the jack shaft, one of said last mentioned pulleys being fixed on the jack shaft to rotate therewith, the other pulley on the jack shaft being mounted for free rotation thereon and for movement axially toward and from the other pulley, coacting clutch faces on the two pulleys on the jack shaft whereby to transmit motion therebetween when the clutch faces are interengaged, an endless belt connecting the motor shaft pulley and the loose pulley on the jack shaft, a second endless belt connecting the fixed pulley on the jack shaft and the off-balanced shaft pulley to produce cooperation thereof with consequent vibrations of the table top vertically of the stand, the endless belt driving the off-balanced shaft being disposed in a generally vertical direction and with sufiicient slack endwise thereof to leave the table top free for vibrations vertically of the stand, control means providing for axially moving the loose pulley on the jack shaft toward and from the fixed pulley thereon, whereby to engage and disengage the clutch faces to cause operation and non-operation of the jack shaft and the off-balanced table top shaft, a thrust bearing on one end portion of the jack shaft, a thrust bearing on the stand, a coiled compression spring extending about said end portion of the jack shaft between said thrust bearings, said spring urging the jack shaft axially in one direction, and a brake comprising two coacting parts, one fast on the jack shaft and the other fixed with respect to said stand, and one of said parts normally interengaging with the other when the jack shaft is shifted axially in response to tension of the spring whereby to hold the jack shaft against rotation, the control means, when operated to axially move said loose pulley on the jack shaft to cause engagement of the clutch faces of said pulleys, shifting the jack shaft counter to tension of said spring and thereby releasing the brake and freeing the jack shaft for operation.

ROY EMMONS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,352,225 Sargent Sept. 7, 1920 1,363,275 Sargent Dec. .28, 1920 1,908,104 Bell May 9, 1933 2,269,788 Schenk Jan. 13, 1942 FOREIGN PATENTS Number Country Date 819,492 France Oct, 19, 1937 

